hodges



Fb. 3, 1931. A. B. HoDGEs 1,790,708

VARIABLE RATE CHEMICAL FEED PUMP Filed Sept. 15, 1928 2 Sheets-Sheet l Feb. 3, 1931. A. B. HoDGEs 1,790,708

VARIABLE RATE CHEMICAL FEED PUMP Filedsept! l5. 1928 2 Sheets-Sheet 2 Jaz/mi@ Patented Feb. 3, 1931 UNITED stares rarest ortica .ALBERT B. HODGES, OF CHICAGO, ILLINOIS, ASSIGNOR TO GENERAL ZEOLITE COMIANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS VARIABLE-RATE CHEMICAL FEED PUMP Application led September 15, 1928.

The present invention pertains to pumps of the reciprocating plunger type, and resides in an improvement which when incorporated in such a pump will render the same particularly adaptable for use in those watersoftening plants where a pumpl is needed which will feed the chemical to the water in a constant proportion regardles of fluctuations in the rate of flow of the water.

The reciprocating plunger pumps heretofore used for that purpose have not been entirely satisfactory owing to the fact that it is practically impossible for an operator, even by making frequent adjustments to the pump, to maintain anything like a constant proportion between the rate of flow of the chemical and the rate of flow of the water throughout fluctuations in the latter.

The object of the invention is to provide `a novel pump control mechanism which, when used in water softening plants where the rate of flow of the water fluctuates, will automatically vary therate of flow of the chemical in vconformity with variations in the rate of liow of the water.

While the foregoing statements are indicative ina general way of the nature of the invention, other objects and advantages will be evident to' those skilled in the art upon a full understanding of the construction, ar-

rangement and operation of the novel pump control mechanism.

One form of the invention is presented herein for the purpose of exemplification, but

it will of course be appreciated thatthe invention is susceptible of embodiment in `other structurally modified forms coming equally within the comprehensive scope of the appended claims. D In the accompanying drawings:

Fig. 1 is a side view of a chemical feed pump equipped with the control mechanism of the invention;

Fig. 2 is an end view; and

Fig. 3 is a top view. v

The pump shown in the drawings consists of a plunger 10 which reciprocates vertically within a casing 11. On each upstroke of the plunger, a certain quantity of the chemical being fed is drawn into the casing past a Serial No. 306,117.

one-way valve 12 in a supply line 13 connected with the bottom of the casing, and, on

each downstroke, an equal quantity is forced out of the casing past a one-way` valvele in a feed line 15 connected with the side of the casing. Y

rlhe plunger 10 is connected at 16 with a electric motor 23 through suitable reduction gearing located in a housing 24.

rlChe upward movement of the cross head 17 is limited in any one of a number of positions by a cam 2,5 which engages at 26 with a portion of the cross head which is forwardly n offset with respect to the portion with which the roller 19 engages. IThe cam 25 is secured to one end of a shaft 27 which is journaled in a bracket 28 carried by the guidevr rods. A pulley 29 is secured to the other end of the shaft 27, and isgrooved helically to receive two or more turns. of a cable 30. The cabley 30 extends from the pulley 29 in one direction over two idling pulleys 31 down to a control float 32 in a tank 33,1 and extends in the other direction over any idling pulley 34: down to a counterwelght 35. .l

The float 82 is caused, by any means suitable for the purpose, to rise or descendin conformity with any increase or decrease in the rate lof flow of the water, and, since the elevation of the float determines the angular position of the cam 25, any change in the rate of flow of the water will cause a corresponding change in the angular position of the cam, resulting in a corresponding change in the length of the stroke of the plunger and a corresponding change in the rate of flow of the chemical through the feed line to the water.

In the particular position of the cam shown in Fig. 2, wherein the shortest radius of the cam isdirected toward the cross head, the

plunger of the pump is permitted to take a full stroke. When the cam is rotated in a clockwise direction, by reason of the float lowering, progressively longer radii of the cam are directed toward the cross head, shortening the stroke of the plunger in proportion to the extent to which the cam is rotated in that direction. Should the cam be rotated in that direction to such an extent as to direct the longest radius of the cam toward the cross head, the cross head would be held by the cam against all movement, and,

while the roller would continue to revolve as before, there would be no flow fromthe pump.

JV here the float 32 is connected up with the flow of the Water in rsuch a way asl to cause the vertical movement of the float to be in direct proportion to the change in the rate of flow of the water, the cam will be spirally shaped, as shown in Fig. 2, but, where other hook-ups are employed for the float, the cam Y will of course have an appropriately changed The construction herein disclosed permits this leakage to be compensated for, if desired, as follows: The cam, instead of being made of such shape as to permit of a stroke exactly corresponding to the flow of the water, may be so shaped as to increase the stroke to correspond both with the increased or decreased flow of the Water and the in` creased or decreased leakage. Thus the radii of the cam may be each increased by a uniform amount, or the radius. at one point in the cam may be increased a proportionately di'erent amount than the radius at another point.

A pump embodying the present invention is capable of delivering a stream under pressure, automatically varying the rate of flow, and automatically compensating for pump leakage at different lengths of stroke. Such a pump, While particularly Well suited for use asa chemical feed pump because of such characteristics, is obviously susceptible of many other diversified and advantageous applications.

I claim:

l. In a variable rate feeding mechanism, a reciprocating pump, means for operating the pump at a constant speed, means includ ing a cam for limiting the stroke of the pump, and means for automatically adjusting said limiting means While the pump is in operation to vary the rate of flow.

2. In a variable rate feeding mechanism, a reciprocating pump, means for operating the pump at a constant speed, a rotatable cam for limiting the stroke of the pump in one direction Without limiting it in the other, and a ioat control means `for automatically rotating the cam while the pump is in operation, Wh'erebyto vary the rate of flow.y

3. In a variable rate feeding mechanism, a reciprocating pump, means for operating the pump, a rotatably mounted cam for limiting the stroke of the pump, and means for r0- tating the cam While the pump is in operation, whereby to vary the rate of'flow.

4. In a variable rate feeding mechanism, a pump having a plunger, a cross head connected with the plunger, powier operated means for moving the cross head in one Ydirection, spring means for moving the cross head in the opposite direction, an adjustably positioned stop for limiting the movement of the crosshead in the direction in which it is moved by said spring means, and means for adjusting the position of the stop While y the pump is in operation, whereby to vary the rate of flow. Y

5. In a variable rate feeding mechanism, a pump having a plunger, a cross headl connected with the plunger, a motor, a shaft, a power-transmitting connection between the motor and the shaft, an eccentric on one end of the shaft which engages with the cross head and moves it in one direction, a spring which engages with the cross head and moves if in the opposite direction, a rotatably mounted cam which engages With the cross head andlimits the extent to which it is moved under the action of the spring, and

meansfor rotating the cam, whereby to vary y the extent to which it is moved under the.

action of the springs, and means for rotating the cam, whereby to vary the rate of flow.

7. In a variable rate feeding mechanism, a reciprocating pump, means for operating the pump at a constant speed, means for: lmiting the stroke of the pump, means for indicating the rate of flow in an associated apparatus, and means operativelyvconnected with said indicati-'ng means for adjusting d ist CII

flow in the associated apparatus regardless of changes occurring in the latter.

8. In Water softening apparatus, means for indicating the rate of flow of the Water being treated, a reciprocating pump for effecting a flow of the chemicals to the Water, meansV for operating the pump at a constant speed, means for limiting the stroke of the pump, and means actuated by said indicating means for adjusting said limiting means whereby to Vary the rate of iioW of the chemical in conformity with variations in the rate of-ow of the Water to maintain a constant proportion therebetween.

9. In a Variable rate feeding mechanism, a reciprocating pump, means for operating the pump, means for changing the stroke of the pump to increase or decrease the rate of flow through the same, and means for automatically compensating for leakage through the pump at any particular length of stroke.

In testimony whereof I have hereunto subscribed my name.

ALBERT B. HODGES. 

